Transmission and reaction torque device



5, 1953 o. R. KUSTER ET AL TRANSMISSION AND REACTION TORQUE DEVICE 4 Sheets-Sheet 1 Filed March 51, 1949 A 5 S E 0 v, R s i m flaw m a w mp. n m W M a? M Y B N J m N Q N a 9 mm R 8 w. QN

1953 o. R. KUSTER ET AL 2,649,816

TRANSMISSION AND REACTION TORQUE DEVICE Filed March 31, 1949 4 Sheets-Sheet 2 INVENTORS 07-70 A. M1751?! F455;? 6'. $50

Aug. 25, 1953 o. R. KUSTER ET AL 2,649,816

TRANSMISSION AND REACTION TORQUE DEVICE Filed March 51, 1949 4 Sheets-Sheet 3 INVENTORS. drra xP. Kai-75F. /Po55@r 0. P/Ep.

ATTORNE Aug. 25, 1953 o. R. KUSTER ET AL TRANSMISSION AND REACTION TORQUE DEVICE Filed March 31, 1949 4 Sheet s-Sheet 4 Patented Aug. 25, :1953

, N ED ATE OFF C TRANSMISSION 3ND REACTION TORQUE j I .DEVICE Otto Richard- Kuster, Brooklyn, and Robert C.

"nierh c'arle Place,'.N. Y., assignors to Knowles Associates, New York, N. Y a partnership premiu 1, 1949, Serial No. 84,516

.lll'clai m. (Cl. 745 70 This invention relates to centrifugal separators and to differential speed-' drives for "machines which operate at high speeds with-"alow -speed differential between parts which' react on" one another. This problem is of;-particularimportance in heavy duty centrifugal machines such as are employed for effecting the continuous separation of the heavier --constituents-of a liquid suspension'from the lighter constituents thereof and is herein shown as embodied in a centrifuge of the solid bowl type, although many of the features of the invention are-applicable to other types of machines.

It had been recognized-for many, years'prior to our resent invention that a simple direct drive for a part operating withja speed differential from the main rotating machineis notfeasible because the reaction of the parts onone another which, even though slight in itself, creates an excessive power demand when it is transmitted back to the power source at the high speed of rotation. Theoretically, this power need not be lost but can be recycled into the main drive,- but practically the result is to impose such high horsepower loads on the transmission mechanism as torequire excessively heavy apparatus and to produce power losses due to friction which may be even greater than the total useful power load. Thus, for example, if the driving motor drives twogearsof slightly different diameterj-one connectedto a centrifuge bowl for operation at 1'000 R. P. M and the other to a scraper for removing solids from the bowl, operating FfR. P. M. faster, the power actually required to "o erate" the scraper at lower R. P. M. relative to the bowl may be of the order of five horsepower which 'at s R1" would be a torque of 5250 ft.- lbs'."

since, however, it is necessary to applythistorque to a drive shaft which moves with the full speed of the centrifuge (assumedin the simple example to be 1000 R. P. M.) plusior minus) the differ: ential speed, the powerfrequiredT on th'e' drive shaft is not 5 H. P. but that equivalent to the horsepower developed by the torque of 5 250 ft.

lbs. at 1005 R. P. M; whichismoan;

main drive shaft through thetransmission gear- 2 ing in opposition to the same horsepower transmitted back along itas the reaction. Although these high circulating horsepowers are thus balanced out, they do nevertheless figure in the efficiency of the apparatus, so that a low percentage efficiency loss becomes a high actual power loss. Moreover, all transmission parts must be made heavy and expensive because of the need for carrying the high fcirculating power load.

It is an object of the present invention to provide an improved apparatus which can give such a dual speed drivewith greater economy and reliability. I I v H More particularly it is an object of the invention to provide an eificient and economical and reliable centrifugal separator.

The problems attacked by the invention have been particularly significant in centrifuges used for effecting the separation of the water from the fine coal and coal fines, which are end products of the hydraulic beneficiation treatment of coal. The invention will therefore be described herein with reference to such application.

With the foregoing and other objects in view the invention aims to provide a drive for rotating machinery and especially for centrifuges in which parts are driven at high speed and at the same time operated, against substantial resistance, at a slow relative speed between them.

Another important feature of the invention is the provision, in the differential drive mechanism by which one rotor is driven at a different speed relative to another rotor (e. g. a screw in a centrifuge to produce the conveying action lengthwise of the bowl), of means whereby the difference in speed may be easily and quickly adjusted, e. g. to suit different materials to be treated.

In existing machines the relative speeds of the rotors could usually be changed only by replacing the differential gear unit by another with another gear ratio. In the novel centrifuge of the present invention a stationary gear shift unit permits the speed change to be made easily and directly and with no substantial loss in production by the machine.

I Still another important feature of the invention is the use of reaction means at the primary eflluent discharge for recovering some of the power employed in bringing the eiiiuent to the point of discharge.

Another feature is the utilization of kinetic energy of the separated solids to break them up into small pieces-which is referred toherein as atomizingand distribute them in a drying atmosphere in a spray dry tower or chamber.

Other objects, important features and advantages of the invention, to which specific reference has not hereinabove been made, will appear hereinafter when .the following description and claim are considered in connection with the ac companying drawings, in which- Figure 1 is a side view partly in longitudinal vertical section and partly in elevation of a centrifuge embodying the present invention;

Figure 2 is a section on the line 2-2 of Figure 1;

Figure 3 is an enlarged longitudinal vertical section through the gear reduction and speed changing mechanism; and

Figure 4 is a diagrammatic sectional view showing the apparatus of Figures 1 and 2 combined with a spray drying tower for drying the cake as it discharged from the secondary centrifuge.

In the illustrative embodiment of the invention a two-stage solid bowl centrifuge machine is shown as comprising a low speed rotor and a high speed rotor revolving at different speeds about the same axis. The low speed rotor herein shown comprises a core is connected by end heads l2 and M to the shafts it and is which support the low speed rotor and an outer, secondary centrifuge bowl QB-A connected to shaft I6 by the end head 22. A scroll 24 on the core It] serves as a screw conveyor to move the concentrated solids along the primary centrifuge bowl 25 toward discharge outlets 25.

The driving or power input shaft is is hollow and is mounted in a self-aligning roller bearing 28. This shaft is driven from any suitable source of power through a multiple V-belt pulley 34 connected thereto. The low speed power output shaft [8 is keyed and/or splined through the shaft H! to the flange or spider 32 of a differential gear reducer, hereinafter more fully to be described.

The high speed rotor, which revolves at a few revolutions per minute more than the low speed rotor, draws its driving force from the low speed rotor through the differential gearing of the present invention, as more fully set forth hereinafter. Like the low speed rotor, it comprises a core 34 carrying a screw conveyor scroll 36 r for the outer, secondary centrifuge, and a bowl 25, for the primary centrifuge, these two portions of the high speed rotor being connected together and carried by end plates 38 and 4B which are carried, respectively, by the bearing 42 on the hollow drive or power input shaft It and by the hollow high speed drive shaft 44 supported in the roller bearing 46. At its outer end the shaft 44 is connected to and turns with the differential gear housing 48.

The two-stage centrifuge machine shown and thus broadly described is more particularly described and claimed in a copending application of R. C. Ried aand C. L. Knowles, filed March 31, 1949, under Serial No. 84,638.

The connection between the low speed rotor Ii] and the high speed rotor 25, by which the high speed rotor is driven from the low speed rotor at a diiferential speed, will now be described.

Reduction gearing is contained in a rotating housing 48 which is connected to the high speed shaft 44 of the centrifugal apparatus andserves as one element of a differential (in this case a planetary gear system) 58, 54, 56. The low 4 speed shaft [8 of the centrifugal apparatus is connected to the intermediate element 59 of the differential gear system; and the third element of the differential system is connected through the gear system 60, 6'2, 10, 12 to the control shaft 14, which is driven clockwise or counter-clockwise from the first element of. the differential through the housing 48 and the gear system contained in the housing 84. As will presently appear, the drive ratio between the bowl 25 and scraper 24 is predetermined, in the example illustrated, by connecting the bowl 225 to the annular.

gear 54 of the differential and the scraper 24 to the spider 3 2, which carried the planet gears, and thenconnecting the sun gear to the annular gear through a gear train. However, any one of the three elements could be connected to the'bowl'and any of the remaining two connected to the scraper, whereupon the third would become the reaction element to be connected either to the bowl or the scraper through a gear train or other torque converter, which may be of fixed ratio or, as will appear below, is advantageously of the variable ratio type.

As above pointe'd out, the low speed rotor, which is driven from any suitable source of power through the belt pulley 30, has a power take-off shaft [9 connected to flange 32 at the right in Figure 1 which serves as the spider of the differential-gear reducer shown in enlarged detail in Figure 2. The spider 32 carries three planetary gears 58 mounted on stub shafts 52 bolted to the spider 32. These planetary gears 53 rotate the housing 48 of the differential gear by meshing with the internal annular gear 54 which is firmly attached to the inner wall of the housing 43. The center pinion or sun gear 56 is driven from the planetary gears 59 and is keyed to a shaft 58 having keyed to its other end a spur gear Gil at the center of a second reduction stage 85, including also the pinions 62 each keyed to a shaft 64 rotatably mounted in the transverse partition 66 and the end wall 68, respectively, of rotating housing 48, with which the pinions E2 revolve in an annular path about the axis of gear 50. Each shaft 64 carries a second gear 'lil keyed through it to one of the pinions 62; and these in turn mesh with and revolve about the central pinion 12 keyed to shaft 14, thus completing the power transmitting gear train from the shaft l8 to the shaft 14. It will be evident that the speed ratio established between the gearsfiil and 12 depend not only on the gear ratios (i. e. the number of teeth on the respective gears) but also on the rotation of the housing 48 relative to shafts 58 and '14, respectively.

In the reduction gearing of existing centrifuges and the like, the reaction end of the differential gear is held stationary by clamping it to a bracket attached to the base or it is driven by a separate motor. In the improved transmission of the present invention, on the contrary, the reaction is taken through a reduction gear back to one of the power shafts l8 and e. g., through the housing 48 to the power output shaft 44. In the exampleshown, the shaft 14 rotates at onefifth the speed of rotation of theshaft l8, in either a clockwise or a counter-clockwise direction, thusadding to, or subtracting from, the speed transmitted from shaft 74 to the rotary housing 48.

In the illustrative embodiment of the invention, two bevel gears 16 and 78 are mounted on the shaft 14 to rotate freely thereon, except when connected thereto as hereinafter described. Each or these bevel gears I6 and ts meshes withthe bevel pinion 88 which is keyed to a vertical shaft .82 mounted toturn in bearingsin the base of the housing 84. Also keyed to the vertical shaft 82 is a bevelgear 86 which engages a bevel'pinion 88. The bevel pinion 88 is keyed to a hollow shaft 98 concentric with the shaft 14, the hollow shaft 98 being flanged at its end outside the casing 84 and the, flange bolted to the end wall 68 of the housing The speed change iseffected by means of a dog clutch sleeve 92 keyedto the shaft I4 between the gears I6 and 18 but is-longitudinally slidable thereon and is provided with an annular groove 94 into which pro-jectsa'yoke 96 of a clutch pivotally mounted on shift lever 98 fulcrumed at I88 on the housing 84. By moving the clutch shift lever 98 in a clockwise direction in Figure 3, the clutch sleeve 92 will be moved to the left to'cause its teeth to enter corresponding recesses in the hub of the bevel gear I6, thus locking this gear to the shaft I4 and causing the hollow shaft 98 to be turned in the same direction relative to shaft I4, through the bevel pinion 88, the bevel gear 86 and the bevel pinion 88. In a similar manner movement of the clutch lever 98 in a counterclockwise direction will cause the corresponding teeth on the other end of the clutch sleeve 92 to enter the corresponding recesses in the hub of the bevel gear I8 and thereby, through the connections above described, effect the rotation of the hollow shaft 90 in the opposite direction, relative to shaft 14. It will be understood, however, that this reversal will not ordinarily produce a change in the absolute direction of rotation of shaft 98 and housing 48, but merely reverses the direction of rotation of shaft 14, thereby adding or subtracting an increment of rotational speed in the planetary system 56, 58, 54.

Illustrative speeds and gear ratios are here given to show the effect of the operation of the gear reducing and gear shifting mechanisms hereinabove described. The shaft l8, which is connected to the low speed rotor I8, is driven at a speed. of 600 R. P. M. The gear ratios are as follows:

Spur gears 12 and I8, ratio 3:1

Spur gears 82 and 88, ratio 3:1

Planetary gears 56, 58 and 54, ratio 4.44:1 Overall ratio: (3 3 4.44) :1=40 1 With the low speed rotor driven at 600 R. P. M. from a 250 H. P. motor, it is estimated that the power to be transmited'by this differential gear set will be about 125 H. P.

In the bevel gear reducer, the gears I6 and 88, or 18 and 88, have a gear ratio of 2.5:1; gears 86 and 88 a 'gear ratio of 2.06:1; overall ratio- (2.5 2.06 :1=5.15:1.

If the shaft I4 be so geared through the gearing in the housing 84 that it is driven at a speed of approximately 120 R. P. M. in a direction opposite to the direction of rotation of the centrifuge, we then have a differential speed between the high speed rotor 25 and the low speed rotor I8, computed as follows:

Adding the 120 R. P. M. to 600 R. P. M. and divide by the gear ratio in the gear housing 48, as follows:

E L-Wis R. P. M.

which is the differential speed between the high and low speed rotors of the centrifuge. If the shaft I4 rotates in the same directionas the shaft I8 the equation will thenbe Thus, by shifting the lever 98 the differential speed between the low speed rotor and the high speed rotor may bechanged from the 12 R. P. M. differential to the 18 R. P. M. differential and vice versa, i. e., from 612'to 618 R. P. M. on the high speed rotor and its drive connection.

In the primary, stage the bowl proper, that is the part in which the pool is carried under centrifugal-action, name1y the rotor 25, will be rotated at 12 or 18R; P. M. faster than the low speed rotor I8. In the secondary stage, however, the bowl proper, that is the part 28, since it is connected to the low speed rotor I8 will be rotatedat 12 or 18 R. P. M. less than the scroll carrying part 34 which is connected to the high speed rotor 25. Because, however, of the considerably increased diameter of the secondary bowl 28, the gravity action of this bowl, by reason of the greater peripheral speed, will be considerably higher than the gravity action of the bowl 25.

As shown more particularly in Figures 1 and 2 'of the drawings, the discharge openings I82 in the end plate of the high speed rotor 25 of the primary centrifuge may be provided with discharge nozzles or jets I82 so arranged tangentially to their path of rotation about the axis of the rotor that the discharge of the effiuent from the centrifuging operation is in a direction opposite to the direction of rotation of the rotor, thereby serving as reaction jets to apply some of the energy of the rapidly rotating liquid for driving the rotor.

In Figure 4 is shown diagrammatically an arrangement for delivering a dry granular or powdery product. In this case the centrifuge (e. g., one as shown in Figures 1 and 2) is surrounded at its solids discharge end with a drying chamber I86 into which the discharged solids are thrown by centrifugal force. Advantageously the solids discharge edge I88 of the secondary bowl 28a is serrated, corrugated or castellated or otherwise designed to break up the cake of concentrated solids into relatively small pieces so as to give high proportion of surface area exposed to the atmosphere of the drying chamber. A drying gas such as heated air, for example, or furnace gases-is blown in from pipes I I8 and nozzles I II into the bottom of the spray drying tower or the discharge housing may be heated by gas burners I I I. This passes up around the discharging bowl 2811 with a velocity sufficient to delay substantially the fall of the pieces of solids thrown off from the edge I88. Coarser particles will fall countercurrent through the flow of drying gas into the channel II2 where it is carried off by the screw conveyor I14. Lighter particles may be carried up through the tower into the settling chamber I I6 from which they settle into the channel H8 and are conveyed to a suitable discharge. The used gas passes off at the top I28 and may be drawn off by fan I22.

We claim: 1

A dual-speed drive for maintaining two operating parts respectively at different high rotational speeds against a reaction torque between them, one of said operating parts being independently driven and the other of said operating parts being driven by said one part through said dual-speed drive, said dual-speed drive comprising a planetary gear system including sun, planetary and annular gears and in which the =12 R. P. M.

annular gear is connected to the higher speed operating part, the planetary gear is connected to the lower speed operating part and a mechanical connection interconnects said sun gear and annular gear independently of said planetary system, said mechanical connection including a gear train having a reversing mechanism and a manually operated member for actuating said reversing mechanism to reverse the direction of the torque transmitted by said gear train.

OTTO RICHARD KUSTER.

ROBERT C. RIED.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,227,456 Lafitte May 22, 1917 1,611,989 Behr Dec. 28, 1926 1,655,425 Laughlin Jan. 10, 1928 Number Number 8 Name Date Henderson et a1. Apr. 21, 1931 Ab bona 1- May 5, 1931 MacIsaac Oct. 11, 1932 Trump Nov. 7, 1933 Van Ackeren Nov. 28, 1933 Campbell May 2, 1939 Jahn Dec. 26, 1939 Szekely May 14, 1940 Jandasek Dec. 5, 1944 Pattee Jan. 6, 1948 Howe Jan. 11, 1949 I Hussain July 4, 1950 Mount Oct. 17, 1950 FOREIGN PATENTS Country Date France Nov. 9, 1942 'France Mar. 30, 1948 

